“SO, WHY are you wearing Google Glass?” I ask the man ahead of me in the coffee line at Ubicomp, a computing conference in Zurich, Switzerland. He responds enthusiastically that he is trying to work out how people with diabetes could use Glass’s camera to recognise the nutritional value of the food they eat and use that to predict their glucose levels, helping them better cope with their condition.

The wearer is Subrai Pai of the Georgia Institute of Technology in Atlanta, and his idea is just one of …